It might help to get a good answer if you post what type of slide you have or post a pic of the slide extended to we could see the operating system. You description is a little hard to understand when you say not level do you mean out at the top or bottom or is it tilted from one side to the other.
Jake my sidekick (yellow Lab)
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho